Studies in an acute in-vivo cat preparation to study simultaneous myoelectric activity and intraluminal pressures of the distal ileum, ICS and colon to opiates. The aims are to evaluate the opiate receptor types and sites in this area and to investigate the role of opiates in a number of intrinsic reflexes. The brain-gut axis will be studied using a chronic cat model and intracerebroventricular injections of opioids and peptides. The opiate-receptor properties of human ileal, ICS and colonic smooth muscle will be studied in-vitro, using tissue removed in surgery.